Electric connecter



Feb. 12, 1935. C GREEN ELECTRIC CONNECTER Filed Feb. 28, 1921 "Fig.2.

n w@ o e r t0 mii v M 4 fl TmMWMS m m a y b .Patented Feb. 12, 1935ELECTRIC CONNECTED Charles M. Green, Swampscott, Mata, assignor toGeneral Electric Company, a corporation of New York Application February28, 1921. Serial No. 448,520 as Claims. (01. 200-152) The presentinvention relates to electric current conveying parts for electricdevices, and particularly to sealed-in conductors for devices containinga body of mercury as, for example,

mercury switches, mercury rectifiers, arc lamps,

and the like.

Certain oxidizable refractory metals, particu larly tungsten andmolybdenum, have been found to be fully as satisfactory as platinum forsealing into glasses having substantially the same thermal coemcient ofexpansion as the sealed-in metal. A thin coating of the oxide whichforms on the metal when the seal is made helps in the production of apermanently gas-tight seal, but the poor electrical conductivity of theoxide zone beyond the glass introduces a relatively high (contact)resistance between the leading-in-wire and a body of mercury. The oxidescan be cleaned off of the metal previous to sealing of the 20 glassflare into the bulb, but, ordinarily, the heat required to seal in theflare and to properly anneal the glass, reoxidizes the metal, and it isextremely difiicult, if not impossible, to remove or reduce this oxideon the lead wire inside of the bulb. Oxide of tungsten may be reduced byhydrogen at a high temperature, but the reduction temperature is abovethat which the glass, even heat resisting glass, will stand.

In accordance with my invention, vI have provided a leading-in-conductorwhich overcomes this difliculty and which consists of a refractorymetal, such, for example, as tungsten, tipped with a metal, such, forexample, as nickel or iron, referred to in some of the appended claimsas of the iron group, the oxide of which may be reduced by. hydrogenwithout affecting the glass, thereby cleaning the surface of the metaltip and even going so far as to have the tip wet by the mercury. By thismeans the best possible connections between tungsten leading-in-wire andmercury is obtained, and the interaction of the hydrogen, the mercuryand the metal electrodes is such that the connecter is substantiallynondeteriorating.

The accompanying drawing shows for illustrative purposes in Fig. 1, as aside elevation partly in section, a mercury switch or contactorcontaining a leading-in-conductor embodying my invention; and in Fig. 2aleading-in-wire sealed into a glass flare.

This switch bulb comprises an envelope 1 consisting of sodium magnesiumbore-silicate glass (also known to the glass trade as G 702 P, Corning(N. Y.), Glass Works), into which conductor 2 of tungsten, molybdenum orthe like, referred to some of the appended claims as a metal of thetungsten group, may be sealed in accordance with Weintraub Patent1,154,081 of September 21, 1915. G 702 P glass contains an appreciableamount of lead. The envelope contains two pockets 3 and 4. Into thesepockets extend reentrant portions 5 and 6 of the envelope, into whichare sealed the conductors 2 and 'I. The envelope or bulb 1, contains abody of mercury 8, completing the electrical circuit between theconductors 2 and 7, the quantity of this mercury being so proportionedthat when the bulbis tilted the circuit" is broken by separation of themercury body into two parts. To assist in this break ing of the mercurybody, small indentations 9 and 10 may be formed in the wall of the bulb.After having been carefully evacuated the bulb is filled with dryhydrogen at substantially atmospheric pressure. The conductors 2, 7, maybe assumed for the purpose of illustration to be of tungsten.

In accordance with my invention a globule 11 of an easily reduciblemetal, for example, nickel or iron, is applied prior to the sealing-inprocess to the end of the tungsten wire. The tip may be applied bydrawing an arc in hydrogen between the tungsten wire and a nickel wire..The nickel preferably is connected to the positive terminal and thetungsten to the negative terminal of an electrical circuit. The tungstenbeing held below the nickel, the two terminals are brought together,then separated, forming an are which melts the nickel and reduces theoxide of tungsten on the tungsten wire, thereby cleaning it, and theglobule of nickel is dropped off the nickel wire down on to thetungsten, forming a bead on the end of the tungsten wire. The tungstenwire may then be sealed into a flare tube 12, as shown in Fig. 2. Aglobule of nickel, 13, preferably is deposited on the opposite end ofthe wire as well, to assist in the connection of the protruding end ofthe tungsten wire to an electric conductor 14, which may consist ofcopper, or other suitable metal. The copper lead is electrically weldedtq 'the nickel globule 13 on a tungsten lead after the bulb has beenexhausted. A small quantity of'suitable cement is applied where thetungsten wire comes up through the flare tube12 above the main bulb asshown at 15. This protects the glass from being injured by the heat ofthe arc whenthe copper lead iswelded on to the leading-in-yvire withinto of the glass, and furthermore, gives additional support to the leads,strengthening same.

When the tungsten wire tipped with nickel has been sealed into the glassflare tube, the nickel is naturally more or less oxidized. The oxide maybe removed by grinding, but when the flare is sealed into the bulb thetemperature required for the sealing in and proper annealing of theglass is suflicient to oxidize both the nickel and the tungsten. Thenickel is subjected to the reducing effect of hydrogen while the entirebulb is heated to a temperature at which a reduction of the nickel oxidewill take place, say, about 500 C. This treatment is repeated a numberof times with fresh fillings of hydrogen to replace the hydrogen whichhas combined with the oxygen of the nickel oxide, reducing same andforming water vapor. It furthermore effects the reduction of the nickeloxide at a temperature which may be employed without injuring the glass.The nickel should be free from oxide, and under these conditions thenickel may be wetted by the mercury, or will be cleaned so that therewill be low resistance connection between the tungsten leading-in-wireand the mercury. Furthermore, it is necessary that there should be afairly large contact surface between the leading-in-wire and the mercurydue to the fact that mercury has a high specific resistance, 94 10* incomparison with nickel 10.7 10" and tungsten 7 l0 After the nickel oxidehas been reduced the bulb is evacuated, filled with pure mercury undervacuum, impurities being not over one part in a million. The bulb thenis filled with dry hydrogen at atmospheric pressure, and is sealed offin. the usual manner.

The cement is then placed around the tungsten leads as they leave theglass bulb, allowed to harden, then the flexible lead 14 is are weldedto the nickel tipped tungsten leading-in-wirc.

Mercury switches embodying my invention have a lower resistance, lowerlosses, and are more reliable than mercury switches containing a simpleleading-in-wire of tungsten, or similar oxidizable refractory metal.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is:-

1. An electric device comprising a glass bulb, a body of mercurycontained therein and a leading-in conductor sealed into said bulb andcontacting with said body of mercury, said conductor comprising anoxidizable refractory metal having joined thereto a tip of metal theoxide of which is reducible at a lower temperature than the temperatureat which said bulb will be injured, said tip being freed from oxide byreduction after the conductor is sealed into the bulb.

2. An electric device comprising a bulb, a body of mercury containedtherein, and a leading-in conductor consisting of tungsten sealedtherein and extending into said bulb, and a metal coating the projectingportion of said conductor, said metal being reducible, after sealing-insaid conductor, and at a temperature sufficiently low to avoid injury tosaid container.

3. In a mercury switch comprising a glass envelope, a body of mercurycontained therein and a tungsten lead sealed into said envelope andprojectingbeyond the seal, the projecting part being of such length asto be subject to oxidation during the sealing and annealing of theglass, the combination of a coating of nickel on said projecting part,said coating being free from oxide by reduction and making a goodelectrical contact with said mercury.

4. In a mercury tube switch, in combination, an

envelope of boro-sllicate glass carrying an appreciable quantity of leadand contacts sealed into the walls of said envelope, said envelope beingfilled with a gas having the property of assisting in removing heat fromthe high temperature points in the envelope.

5. In a mercury tube switch, in combination, an envelope ofbore-silicate glass carrying an appreciable amount of lead and contactssealed into the walls of said envelope, said envelope being filled withhydrogen.

6. In a mercury tube switch, in combination, an envelope of glass havinga coefficient of thermal expansion substantially that of bore-silicateglass and greater than that of fused silica, contacts sealed into thewalls of said envelope, and a con tact making and breaking member insaid envelope for bridging the gap between said contacts.

'7. In a mercury tube switch, in combination, an envelope of glasshaving a coeflicient of thermal expansion substantially that ofDoro-silicate glass and greater than that of fused silica, contactssealed into the walls of said envelope, and a gas assisting in removingheat from said envelope.

8. In a mercury switch, in combination, an envelope of glass having theproperty of withstanding high temperatures and rapid fluctuations intemperature and a well formed thereon of borosilicate glass, mercury insaid switch, and lead wires passing through the wall of the envelope andin contact with said mercury.

9. In a mercury switch, in combination, an envelope of glass having theproperty of withstanding high temperatures and rapid fluctuations intemperature and wells formed thereon of borosilicate glass, mercury insaid switch, and lead wires passing through the wall of the envelope andin contact with said mercury.

10. In a. mercury switch, in combination, an envelope of glasscontaining an appreciable quantity of metal and having the property ofwithstanding high temperatures and rapid fluctuations in temperature,mercury pools in said envelope in the open position of said switch, andlead wires passing through the wall of the envelope and in contact withsaid pools.

11. In a mercury switch, in combination, an envelope of glass containingan appreciable quantity of metal and having the property of withstandinghigh temperatures and rapid fluctuations in temperature, mercury poolsin said envelope in the open position of said switch, and lead wires oftungsten like material passing through the wall of the envelope and incontact with said pools.

12. In a mercury switch, in combination, an envelope of boro-silicateglass carrying an appreciable quantity of metal, wells opening into saidenvelope, and contacts sealed into the walls of said envelope andterminating in said wells.

13. In a mercury switch, in combination, an envelope of boro-silicateglass carrying an appreciable quantity of metal, a well opening intosaid envelope, and dividing the mercury into two pools in the openposition of the switch, and contacts passing through the wall of theswitch and terminating in said pools.

14. In a mercury switch, in combination, an envelope of boro-silicateglass carrying an appre ciable quantity of metal, mercury pools in saidswitch, and tungsten lead in wires sealed in the wall of the envelopeand in contact with said mercury pools.

15. In a mercury switch, in combination, an envelope oi boro-silicateglass carrying an appreciable quantity of metal, mercury pools in saidenvelope in the open position of said switch, and a. gas in saidenvelope having the property of assisting in the removal of heat fromthe high temperature points in the envelope.

16. In a mercury switch, in combination, an envelope of boro-silicateglass carrying an appreciable quantity of metal, mercury pools in saidenvelope in the open position of said switch, tungsten lead in wiressealed in the wall of the envelope and in contact with said mercurypools, and a gas in said envelope having the property of assisting inthe removal of heat from the high temperature points in the envelope.

17. In a mercury switch, in combination an envelope of boro-silicateglass, contacts sealed through the walls thereof, and mercury therein.

18. In a mercury switch, in combination, an envelope of boro-silicateglass having wells opening thereinto, contacts sealed through the wallof said envelope and terminating in said wells, and a body of mercury insaid envelope.

19. In a mercury switch, in combination, an envelope of glass having theproperty of withstanding high temperatures and rapid fluctuations intemperature, mercury pools in said envelope in the open circuit positionof said switch and lead wires in contact with said pools passing throughthe wall of the envelope in sealed relation to borosilicate glasscarried by said wall.

20. In a mercury switch, in combination, an envelope of glass having theproperty of withstanding high temperatures and rapid fluctuation intemperature, mercury in said envelope, and lead wires passing throughthe wall of the envelope in sealed relation to boro-silicate glasscarried by said envelope and being in contact with said mercury in aclosed circuit position of the switch.

21. In an electrical contactor device for electric power circuits, asealed container, electrodes positioned within said container, anatmosphere comprising hydrogen gas filling said container, and a body.of mercury movable to make and break the circuit between saidelectrodes, the latter being composed of a metal of the iron group, saiddevice being substantially non-deteriorating by reason of theinter-action of the mercury, said atmosphere and said metal electrodes.

22. An electrical contactor comprising an elongated hermetically sealedcontainer of insulating material, a quantity of mercury in saidcontainer adapted to ride back and forth on the inner surface of thecontainer and lengthwise thereof when the container is tilted inopposite directions past a horizontal position, electrical conductorscomposed of metal of the iron group within the container in position tocooperate with the mercury to open and close the electric circuitthrough said contactor upon the tilting of the latter, and an atmosphereof hydrogen in the container, the action of the said atmosphere, themercury and said electrical conductors being such that the contactor issubstantially non-deteriorating.

23. An electrical contactor comprising an elon gated hermetically sealedcontainer, a quantity of mercury in said container adapted to ride backand forth on the inner surface of the container and lengthwise thereofwhen the container is tiltedin opposite directions past a horizontalposition, leading-in wires extending through the wall of said containerand being of a material to provide substantially permanent hermeticseals therein, electrical conductors comprising a metal of the irongroup at the inner ends of said leadingin wires and being positioned tocooperate with the mercury to open and close the electric circuitthrough the contactor upon tilting it, and an atmosphere comprisinghydrogen filling the said container.

24. An electrical contactor comprising 9. hermetically sealed container,electrical conductors hermetically sealed in said container andseverally terminating into an exposed portion within the container thatis composed of a metal of the iron group, said exposed portionscooperating with the mercury to open and close the electric circuitthrough said contactor when tilted, an atmosphere comprising hydrogengas filling said container, a quantity of mercury contained within saidcontainer and which contacts with said electrical conductors to open andclose the electric circuit through said contactor, the action of saidatmosphere, the mercury and said electrical conductors being such thatthe contactor is substantially non-deteriorating.

25. A mercury power switch comprising an envelope of glass, mercurytherein, and electrodes, each of which comprises a lead-in sealed intosaid envelope and a terminal portion of metal of the iron group weldedto said lead-in and extending into said mercury.

26. A mercury switch comprising an envelope of glass, mercury therein,and electrodes, one of which comprises a lead-in of a metal of thetungsten group sealed into said envelope and a terminal portion of metalof the iron group welded to said lead-in and extending into saidmercury.

27. A mercury switch comprising an envelope of glass, a mercury therein,and electrodes, one of which comprises a lead-in of a metal of thetungsten group sealed into said envelope above the level of the mercuryand a terminal portion of metal of the iron group welded to said lead-inand extending into said mercury.

28. A mercury switch comprising a longitudinal envelope of glass havingmercury therein, an electrode sealed through the envelope wall andextending into said mercury, an electrode lead-in of tungsten sealedthrough the envelope wall at one end thereof and a terminal portion ofnickel welded to said lead-in and extending into said mercury.

29. A mercury switch comprising a longitudinal envelope of glass havinga well formed therein, mercury in said envelope, an electrode sealedthrough the wall of said envelope and extending into said mercury, anelectrode lead-in of tungsten sealed through said wall above normalmercury levels and a terminal portion of nickel welded to said lead-inand extending into said well.

30. A mercury power switch comprising a sealed envelope of glass,mercury therein, and electrodes, each of which comprises a lead-insealed into said envelope and a terminal portion of metal of the irongroup welded to said lead-in and extending into said mercury, and afilling of hydrogen in said envelope.

31. A mercury switch comprising a sealed envelope of glass, mercurytherein, and electrodes one of which comprises a lead of tungsten sealedinto the envelope and a terminal thereon of oxygen free nickel.

32. The method of making an electrode for a mercury device into which itis sealed which comprises welding a nickel terminal portion to atungsten lead-in portion.

33. In an electrical contactor device for electric power circuits, asealed container, electrodes positioned within said container, anatmosphere comprising hydrogen gas filling said container,

and a body of mercury movable to make and break the circuit extendingbetween said electrodes, the latter having mercury engaging portions ormetal wetted by mercury, said device being substantiallynon-deteriorating by reason of the inter-action of the mercury, saidatmosphere and said metal electrodes.

34. An electrical contactor for making and breaking an electric circuit,including a movable hermetically sealed hydrogen-filled container havinga closed position and an open position, a quantity of mercury therein,leading-in conductors extending through the wall of said container andhermetically sealed therein, electrical conductors of a metal 01 a groupconsisting of nickel and iron at the inner ends of said leadinginconductors and positioned so as to be in contact with the mercury andcomplete a circuit from one leading-in conductor to the other throughsaid mercury when the container is in the closed position, said circuitbeing broken when the container is in the open position, the surface ofsaid electrical conductors being wetted with mercury whereby arelatively low resistance contact is made with the mercury in thecontainer.

35. A mercury switch including a hydrogenfilled glass envelope, a bodyof mercury within said envelope. a pair of leading-in conductorl sealedin said envelope and provided with terminal portions of a metal 0! agroup consisting of nickel and iron for engaging said body of mercury,said terminal portions being wetted with mercury.

CHARLES M. GREEN.

